Various control devices are used to effectively and efficiently maneuver aircraft during various phases of flight. Some control devices are directly attached to wings of an aircraft, such as ailerons adapted for controlling “roll”, i.e. the rotational movement of an aircraft about its longitudinal axis. Spoilers may also be directly attached to aircraft wings to rapidly reduce wing lift when and as desired, particularly during various descent phases of a flight. Flaps are typically also attached directly to the wings to change their aerodynamic shapes for assuring stable flight control during slower speeds, such as during takeoff and landing phases of flight.
FIG. 1 is a fragmentary schematic view of a wing 10, attached to a fuselage 12, the wing and fuselage together depicting a portion of an aircraft 14 configured in accordance with the described related art. The wing 10 has a forward or leading edge 15 which may include deployable slats 16, as yet another wing control device. The wing also has a trailing edge 17 that includes outboard ailerons 18 and outboard flaps 20. The trailing edge 17 may also include inboard ailerons 22 and inboard flaps 24. As noted earlier, the ailerons are used for roll control of the aircraft 14, while the flaps are utilized to enhance lift control at lower speeds, e.g. for takeoffs and landings.
In some instances, the effective deployment of flaps may require translational movements in addition to their normal downward angular movements from stowed positions for creating spaces and/or gaps that need to be controlled for purposes of aerodynamic efficiency. Thus, arrows 26 and 28 indicate the directions, when deployed, of rearward translational movements of outboard flaps 20 and inboard flaps 24, respectively. Typically, ailerons, including the inboard aileron 22 require no translational movement, as do the dedicated flaps 20, 24.
The translational movement or extensions of outboard and inboard flaps 20, 24 of the convergent wing design of the aircraft wing 10 of FIG. 1 would pose an issue of angular interference, if the respective flaps were immediately adjacent each other. Such interference is avoided, however, by portion of the wing 10 that includes the inboard aileron 22, which is positioned between the flaps 20, 24 and involves no translational deployment.
In large turbofan jet aircraft, the functions of a flap and at least an inboard aileron may often be combined into a single or unitary control device called a flaperon. Since both flaps and ailerons are usually attached to the trailing edges of the aircraft wings, flaperons are also likewise attached. Thus, referring now to FIG. 2, the inboard aileron 22 of the aircraft 14 is shown attached to the trailing edge 32 of the wing 10, as shown at an interface 30 of the leading edge 34 of the inboard aileron 22. It should be noted that the inboard aileron 22 may be rotated about a hinge axis 38 into a rigid downward position 22″ (shown in phantom); i.e. deployed from the stowed position shown to a fixed angle along the downward arc of angle B, to function solely as a flap, even though without a gap, since at relatively slower speeds, i.e. during takeoff and landing, the outboard ailerons may be solely relied upon to effectively control roll of the aircraft 14.
Since the inboard aileron 22 also function as a flap, in aviation parlance such control device is also called a “flaperon”, to the extent that it may be called upon to selectively perform both aileron or flap functions, depending on circumstances and/or phases of flight.
When functioning as an aileron, the so-called flaperon 22 is rotated upwardly along arc A from its stowed position as shown, up to and including a limit position 22′ (shown in phantom), to the extent that a functional aileron must be free to move both upwardly and downwardly. Conversely, the flaperon 22 may be rotated downwardly along arc B from its stowed position, down to and including a limit position 22″ (also shown in phantom). Finally, the trailing edge 32 of the wing 10 incorporates an aft-facing cove lip 36, a volume or space in which the leading edge 34 of the flaperon may rotate in close proximity, as depicted in FIG. 2 at the interface 30.
Referring now to FIG. 3, the flap 24 may also be capable of acting as an aileron, and thus as a flaperon. Therefore, the flap 24 may also be variously called a flaperon 24. However, because deployment of the flaperon 24 may involve a translational extension, the physical structure involved in its deployment must accommodate translational in addition to pivotal movement. In the related art structure shown, a hinge panel 40, configured for management of aerodynamic air gaps created during the extension aspect of deployment of the flaperon 24 is coupled to the structure of the cam track mechanism 42 to assure desired angular positioning relative to the wing 10 and the flaperon 24.
Several challenges are presented by such structures adapted to satisfactorily accommodate both angular and translational motion, including the need to assure requisite fail-safe strength and robustness under occasional extreme loads, such as those associated with turbulence and other phenomena routinely encountered in flight. As such, the cam track mechanism 42 includes relatively heavy cam tracks 44 that define paths for cam track rollers 48 that are directly secured to roller links 46. Use of the cam track mechanism 42 has also necessitated the use of a technology called “fusing”, for assuring safety in the event of “jamming” of any of the track rollers 38. Since jamming is an issue to be avoided at all costs, at least two roller links are typically riveted together in a cam track-style mechanism 42 (FIG. 3) for appropriate safety redundancy. Such links are designed to fail in a predictable manner, necessitating additional weight that would be preferably avoided.
Thus, it is desirable to provide novel aerodynamic gap control structures to accommodate both angular and translational movements of flaperons, but wherein such structures can retain robustness and yet be lighter in weight, in the face of increasingly stringent aircraft design requirements.